C. The bottom always has the most energy and at each level it goes down, hence it becoming a pyramid
Answer:
Answer is all of the above.
Explanation:
Reproductive isolation can be described or explained as a collection of mechanisms such as behavioral and ecological mechanisms preventing the members of two or more groups of different species that mate from producing offspring, or if their mating eventually produced offspring, the offspring will not be fertile.
There are things that can make reproductive isolation to occur, they include
* Lack of fit between or among sexual organs.
* Creation of mating location,behavior and time.
* Offspring sterility
Answer :A half- life is the time required for half of the radioactive substance to undergo radioactive decay. In two half lives first half of the original sample decays then in the second half life half of what is left decays.25%
Explanation:
Bc yarn and hair is very identical so therefore hair would be a substitute for yarn
